1. Field of the Invention PA1 2. Description of Related Art
This invention relates to information presentation on a computer display, and in particular to the display of related data from a plurality of sources.
It is often desirable to display information from different, but related, data sources simultaneously on a computer display. For example, when viewing the text of a document in one window, or portion, of the computer display, it might be desirable also view footnotes or commentary associated with that text in another window. Another example would be to view a foreign language text in one window and its English translation in another window. A third example would be to view information stored on a read-only medium, such as a compact disk read-only memory (CD-ROM) in one window and updates or corrections to the read-only information in another window.
Such related data sources may be stored in separate files. They may also be portions of the same file with some means of indicating the related data sources within the file, such as indicator codes embedded within the file that mark the extent of each related data source, or a file header indicating the locations of each related data source in the file.
Many computer programs have been developed for displaying two synchronized views of the same data source. In U.S. Pat. No. 4,428,065 (Duvall et al.), a technique for presenting a magnified view in one window of the text being displayed in another window is disclosed. In the WordPerfect text processor, it is possible to split the computer display screen so that the formatted text is displayed in one window and a synchronized view of the same text, but with all the control codes revealed, is displayed in another window. In the WordPerfect "reveal codes" display, the cursor in one window automatically follows the cursor in the second window.
The simplest way of accomplishing simultaneous viewing of information from different, but related, data sources is to use separate text editors, or other means for displaying data in a window, for each of the related sources of data. However, this requires the user to manually synchronize the viewing positions in each of the windows whenever the viewing position of one of the windows is changed. This may involve moving the cursor to another location in the currently-displayed data, or scrolling another portion of the data into the window. This can be difficult and error-prone when the user cannot quickly recognize how the current position in one window relates to the data being displayed in another window.
In U.S. Pat. No. 5,091,876 (Kumano et al.), a method for synchronizing the viewing position of two windows being controlled by a single program is disclosed as part of an automated language translation system. Kumano utilizes a table indicating the starting location for each sentence in both the original text and the translated text. From that table, it is possible to determine the sentence number for the current cursor position in a window, and the starting location for the corresponding sentence in the other window. This permits the program to keep the text displays and cursor positions of both its windows synchronized.
The technique in Kumano is limited in a nun%her of ways. It only operates with windows or text displays controlled by a single program--the program that contains the sentence starting location table. Furthermore, the technique as described by Kumano only operates on related data where there is a one-to-one correspondence between sentences in each data source.